Derivatives - Components of Gain (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivatives
Realized gain (loss) on derivatives	$ (16.9)	$ 7.0	$ 11.2
Gain (loss) on derivative activity	14.4	5.2	(4.2)
EnLink Midstream Partners, LP | Commodity Swaps
Derivatives
Change in fair value of derivatives	(0.1)	10.1	4.7
Realized gain (loss) on derivatives	14.5	(4.9)	(8.9)
Gain (loss) on derivative activity	$ 14.4	$ 5.2	$ (4.2)